Halogen-5 trimethyl-1,3,3 indoline 2-spiro-3&#39; nitro 8&#39; naphtho (1,2-b) pyrannes



April 7, 1970 R. L. G TRON 3,505,352

ETHYL-l DoLINE 2- Ro-s' NITRO NAPHTHO PYRANN HALOGEN-5 T rileci Feb.

ATTO NEYS United States Patent O 3,505,352 HALOGEN-S TRIMETHYL1,3,3 IDOLINE 2-SPIRO- 3 NITRO 8 NAPHTHO (1,2-b) PYRANNES Ren Lucien Gautron, Sceaux, Hauts-de-Seine, France,

assignor to Compagnie de Saint-Gobain, Neuilly-sur- Seine, France Filed Feb. 1'7, 1965, Ser. No. 433,315 Claims priority, application France, Feb. 18, 1964, 964,157, Patent 1,394,163 Int. 'Cl. C0711 27/ 36 U.S. Cl. 260-326.11 4 `Claims ABSTRACT OF THE DISCLOSURE Halogen-5 trimethyl-1,3,3 indoline 2-spiro-3' nitro 8 naphtho (1,2-b) pyrannes useful in photochromic appli cations, such as light filters. The compounds can be embodied in useful solutions, lms and solid objects.

This invention relates to the photochrome and phototrope sciences. The words photochrome and phototrope are used more or less interchangeably to describe a phenomenon associated with actinic light in which substances change color, become opaque, or absorb one wave length and issue another when affected by the light. The most notable of such compounds are those which respond to the invisible forms of radiation such as infrared and ultraviolet. Known types of these materials have been made use of in the manufacture of variable transmission windows for buildings and vehicles, the purpose of which has been to exclude the heat of the day, automatically and to a degree commensurate with the intensity of the radiation involved, and to regulate the amount of light admitted through the window. Among the methods of use which have been proposed are to coat an ordinary sheet of window glass with a transparent lacquer containing a photochrome, and to dissolve a photochrome in a suitable solvent and sandwich the solvent between two layers of glass.

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photochromes which remain transparent while becoming colored, being thus suitable for windows of vehicles as well as for those of stationary structures. Another object is to provide a class of photochromes among the members of which are a number which yield different colors under excitation, thus providing scope for the efforts of artists and decorators. Another object is to provide a class of photochromes, some members of which color and decolor at different speeds, thus providing rates of change adapted to different conditions.

Another object is to provide a class of photochromes which can be used in liquid or solid solution, which are compatible with typical resins, for instance the vinyls, and which can be embodied in useful solutions, films, and solid objects, such embodiments being capable of wide variation in change of coloration and time of recovery. Other objects are to make such novel photochromic means by simple methods which do not degrade the resins.

The objects of the invention are accomplished generally speaking by photochromic means embodying at least one of the photochromic compounds represented by Formula l, in which at least one of R1, R2, and R3 is from the group consisting of lower alkyl, lower alkoxy, halogen, nitro, hydroxy, cyano, triuoromethyl, and phenyl, the alkoxy, alkyl and phenyl groups of which may bear substituents from the class consisting of halogen, nitro and amino, and R4 is one of the group consisting of lower alkyl and phenyl, and a carrier therefor. Lower alkyl means from 1 to about 10 C atoms.

These photochromic means meet the requirements above stated except that they remain transparent and do not become opaque. When they are incorporated in solutions and irradiated by ultraviolet light, they reveal a band at about 5900 A., the exact position of the band varying according to the nature of the substituents attached to the nucleus. This is a very valuable quality because the location of the spectrum band can be changed by changing the substituents.

A preferred group of these photochromes is as follows:

The principal properties which are desired in variable transmission windows are high speeds of coloration and decoloration; coloration and decoloration operating as a function of the quantity of radiation; stability of the photochrome under conditions of use for long periods; when the object is to exclude or extensively limit the passage of radiation, a maximum absorption of light, that is to say practically complete opacity when the radiation received reaches a predetermined peak value; an absorption spectrum covering, so far as possible, the whole wave length of visible light from 4000 to 7500 in general the coloration or decoloration should take Vplace within a few minutes and preferably within a few seconds following a change in the intensity of the radiation received. Not all of these properties are to be expected of any one photochrome and, indeed, some of them are mutually inconsistent. The art seeks to find photochrome with properties which satisfy particular needs.

It is an object of the present invention to provide The nomenclature is that adopted by the Bulletin of the Chemical Society of France in October 1958. This nomenclature will be maintained in order to avoid the possibility of error in transliteration but it is also to be noted that compound I could be called 1,3,3 trimethyl 2-spiro-3 indoline 8 nitro 1,2(b) naphthopyran.

In general, at least one of R1, R2, R3 should be other than hydrogen.

These photochromes have the power to change color under irradiation when they are dissolved in asolvent, or when they are in a dissolved state in a solid solution in a plastic mass such as a lacquer film, and this property of maintaining their phototropic power after undergoing a change in state is of material value in the construction of variable transmission windows.

These photochromes may be dissolved in solvents and the solution can be entrapped between two sheets of glass to act as a light lter which changes under the impact of different dosages of actinic light. The preferred solvents arethose which have low polarity, for instance hexane and toluene, and because these solvents are compatible with numerous polymers used in the manufacture of lacquers the solutions are valuable for incorporation in films and lacquers.

It is also possible to incorporate the photochrome in a plastic mass, for instance in a plate or sheet of polyvinyl butyral, which is merely illustrative. This particular resin is useful in making sandwich glass and it is even more useful for that purpose when the photochrome has been incorporated in it. A method of incorporating the photochrome in the film is suggested above and explained in more detail in the following examples.

It is also possible to prepare a lacquer or film containing the photochrome, using a volatile solvent in which the photochrome and the organic resin are dissolved, the lacquer being spread on the glass and leaving a transparent ilm containing the photochrome after evaporation of the solvent. Such films are sometimes fragile and may be protected by over coats of glass, plastic, or lacquer.

Attention is drawn to the fact that not all these compounds are colorless in their original state, but in those cases in which an initial color is visible there is a reversible change to a different color under irradiation. It is also to be noted that when the photochromes are incorporated in semirigid bodies such as polyvinyl resins of various sorts, the speed of change from the initial state to the most highly colored state and back again may be slower. This is not objectionable in use because in many instances the rates of change are so rapid in liquid solution as to be diliicult to measure at ordinary temperature. It is consequently advisable to carry out tests on solutions at C. as this reduces the speed of change to values which are more readily determined. The tests solvents, examples of which are given in the following table, and on photochromes incorporated in solid solution in polyvinyl butyral. This resin is transparent, is much used in making sandwich glass, and is adequately representative of the general principles applicable to making resinous photochromes. The photochrome having been dissolved in the solvent and the solvent being compatible with a particular resin, the solution may be incorporated in the resin and the solvent evaporated olf, leaving a transparent solid which responds to actinic light according to the nature of the photochrome employed.

EXAMPLES RELATED TO SOLUTIONS Solutions were made of about l0 parts per hundred of photochrome in the solvents listed and these solvents were irradiated for l0 seconds at 0 C. with a mercury vapor lamp type Philips SP. 500. The color before and after irradiation was noted as well as the time necessary to return the color to its original state. This is called time for de-coloration but it does not mean that a solution which was originally colored is made colorless, but simply that it returned to its original color. In the following table the number of the photochrome tested is given and its identity can be determined from the list hereinabove. The vertical columns show the results of irradiation in different solvents. In every instance the first color is that before irradiation and the second is that during irradiation. The time expressed in seconds is the time required to resume its origina-l form from its excited state. When only a single color appears it indicates that the irradiation did not substantially change the color and that a different solvent should be used with that photochrome. A blank indicates that the particular photochrome was not tried with that particular solvent.

Tetrahydro- Dimethyl Toluene Ethyl formamide acetic acid Butauol Methanol acetate Toluene furan I Yellow Yellow Yellow.-. Yellow Yellow Yellow Ye11ow,

Carmine.- Carmine Carmino..-- Vio1et-.... Violet..." Carmine. 1to2sec lt02sec lto2seo.... Slow..-

Slow el1ow-... Yellow-.. Red Violet VI Co1orless...- C0l0rless Yellow-... Yellow Yellow- Yellow..

Violet Violet Viol Violet. Violet.---

1to2sec...- 1 Sec 1 sec 1 seo 1 sec set forth in the following table were carried out at 0 C. 50 EXAMPLES PERTAINING TO PHOTOCHROMES In the drawing:

Formula l is a general formula for the class of chemical compounds to which the new photochromes belong;

-Formula 2 indicates the probable locations of the double bonds and it is to be noted in this respect that the positions of these double bonds should remain the same; and

Formula 3 represents the preferred reaction, the use of which produces the compound of Formulas l and 2.

In Formula 3 the rst compound is dimethyl-3,3- methylene-Z-indoline. The second reactant is formly l hydroxy 2 naphthalene. The product of this reaction is Formula 1 plus water, the water passing olf as vapor.

It is to be noted that not all of these compounds change color in all solvents. For example, compound V turns yellow-violet in toluene when exposed to actinic light but does not change color when dissolved in methanol. It will also be observed that there is a difference in the tint produced in different solvents in some cases. These variables are advantageous as they provide selectivity. It is also notable that different solvents sometimes produce diiferences in the rate of change such as 1 to 2 seconds in toluene for compound III and 15 seconds in ethyl acetate. This also adds to selectivity.

Tests have been carried out on solutions in the usual INCORPORATED IN POLYVINYL BUTYRAL A sheet of polyvinyl butyral plasticized by butyl sebacate is immersed for 3 to 5 minutes in a benzene solution of 5% photochrome and 5% butyl sebacate. The sheet is then drained and dried to eliminate the benzene. Test pieces of the sheet thus obtained are colorless or faintly yellow regardless of the photochrome employed. The test pieces were submitted at 20 C. to the action of photo flash having an output of 350 joules. The tests consisted in noting the coloration acquired by the test piece as a result of the flash and the length of time required to return to its original color. This is expressed in the following tables:

solution, although this can and should be done when a complete impregnation of a thick piece is desired, but that the resin was immersed in a solvent containing the photochrome, the solvent being at least capable of swelling the resin, the resin being removed from the solvent before actual solution had occurred and after it had absorbed enough of the solution to become to some extent impregnated with the photochrome.

When it is desired to make thick sheets, or for that matter thin sheets, in which a photochrome is uniformly dispersed throughout, the resin may be dissolved in a suitable solvent, the photochrome may be dissolved in the same solvent, and the two may be mixed.

Additional tests were run as follows:

TEST X Chloro-5-trimethy1-1,3,3 indoline 2spiro3 nitro-8 naphtho (1,2-b) pyran was dissolved in benzene at room temperature. The solution was pale yellow verging on colorlessness. It was irradiated at 20 C. for 10 seconds with the light of a mercury vapor lamp of the type described above. The solution was made violet and returned to its original color in 1 second.

TEST Y Trimethyl1,3,3 indoline 2spiro3' nitro-8 naphtho (1,2-b) pyran was dissolved in toluene at room temperature. Its color was as in Test X. After seconds of irradiation with the same lamp the solution became violet and took 1 second to return to its original color after excitation ceased.

Among the advantages of this invention are photochromie composition which include the photochrome and a support or carrier which may tbe a solvent, liquid or solid in which the photochrome is, in effect, in solid solution. These novel manufactures may be colored or colorless in their inert state but they have the general property of changing color when excited by actinic light, especially ultraviolet light. They remain transparent under all conditions. The depth of the color produced is proportioned to the intensity of the exciting source.v The colors produced vary according to the solvent employed. Recovery is extremely rapid in solution in a solvent, is slower when the solvent contains a resin, and is much more retarded when the resin is solid. This class of photochromic materials is characterized by good selectivity as to color and high selectivity as to time of recovery, and this selectivity makes the materials suited to different uses. They have long life without degradation or loss of activity.

As many apparently widely dilerent. embodiments of the present invention may be made without departing from the spirit and scope thereof, it is to be understood that the invention is not limited to the.` specific embodiments.

What is claimed is:

1. The halogen-5 trimethyl-1,3,3 indoline 2-spir0-3 nitro-8 naphtho (1,2-b) pyrannes.

2. Fluoro-S trimethyl-1,3,3 indoline 2-spiro-3 nitro-8 naphtho (1,2-b) pyranne.

3. Chloro-S trimethyl-1,3,3 indoline 2-spiro-2 nitro-8 naphtho (1,2-b) pyranne.

4. Bromo-S trimethyl1,3,3 indoline 2-spiro3 nitro-8 naphtho (1,2-b) pyranne.

References Cited UNITED STATES PATENTS 3,149,120 9/1964 Berman et al 117-33.3 X 3,197,475 7/ 1965 Carboni 117-333 X 3,218,332 11/1965 Heller et al 117-333 X 3,231,584 1/1966 Berman et al.

3,272,646 9/ 1966 Chopoorian et al. 117-333 X 3,290,331 12/1966 Taylor et al 117-33.3 X 3,299,079 1/ 1967 Taylor.

3,321,491 5/1967 Huffman et al. 117-333 X 3,331,854 7/1967 Huffman et al. 117-333 X FOREIGN PATENTS 887,958 1/ 1962 Great Britain.

OTHER REFERENCES Hirshberg and Fischer-Journal of Chemical Society (London) 1954 (Part III) pp. 3129-3137.

RICHARD D. LOVERING, Primary Examiner U.S. Cl. X.R. 

